JPS5927788B2 - Combinatorial conversion process from heavy fractions to LPG - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides for the production of L
A two-stage hydrogen consuming process for selectively producing PG.

Hydrocracking processes are commonly used in converting heavy hydrocarbons to low boiling saturated products.

An economically satisfactory hydrocracking process for LPG production is selective in maintaining high activity over long periods of time while avoiding the decomposition of normally liquid hydrocarbons into undesirable gaseous hydrocarbons such as methane and ethane. There must be.

The present invention uses a catalyst composition comprising a porous carrier material, a Group VI-B metal component, and a Group I metal component in the first-stage hydrocracking zone, and in the second-stage hydrocracking zone. uses a catalyst composition comprising a Group I metal component bonded to a support containing alumina and finely divided mordenite particles.

A solid catalyst that has the property of promoting the so-called acid-catalytic reaction is
It is now widely used in hydrocracking processes.

In some cases, these catalysts have been used to promote reactions that are thought to proceed by carbonium ion intermediates, but in other cases, these acid catalysts have been used to promote hydrogenation-dehydration. A bifunctional catalyst having both cracking ability and hydrogenation ability is provided by combining with the elemental metal component.

In the latter case, the cracking capacity is generally believed to involve a porous, adsorbent, refractory oxide-type acid agent, which typically contributes generally to the hydrogenation capacity. It is used as a carrier for heavy metal components such as Group I or Group II metals of the periodic table or their compounds.

In order to carry out a satisfactory and economically viable hydrocracking process, the prior art has proposed combining crystalline aluminosilicate with alumina material; It is possible to obtain a catalyst that retains an acid function that is substantially greater than the sum of the acidity contributed by each of them individually.

A primary object of the present invention is to improve the process for selectively producing LPG from hydrocarbon feedstocks with boiling points above 600'F.

As will be made clear in the Examples below, the improvement according to the present invention lies in the chemical characteristics of the catalyst composition used in the second stage catalytic reaction zone.

The improved method of the present invention allows for processes with increased activity without sacrificing the selectivity of the catalyst for LPG production.

It is therefore another object of the present invention to provide a process that performs economically for long periods of time as a result of increased efficiency due to the use of improved catalyst compositions.

Therefore, if described in broad concrete terms, the present invention has a boiling point of about 6
The present invention relates to an improved hydrogen-consuming process for selectively producing LPG from hydrocarbon feedstocks of 00'F or higher, the improved method comprising combining the feedstock and hydrogen in a first catalytic reaction zone under hydrocracking conditions. a catalyst composition comprising a porous support material, a Group VI-B metal component, and a Group I metal component, and then directing at least a portion of the first catalytic reaction zone effluent to a second catalytic reaction zone. Pressure at about 30
0 to about 1800 psig, temperature about 6001 to about 850
'F, under hydrocracking conditions including LH8V about 8V about 10 hr-1 and a hydrogen circulation ratio of about 5000 SCFB to about 15000 SCFB (fresh feed basis);
finely divided mordenite particles are reacted with a catalyst consisting of a uniformly distributed alumina support material bound to a Group I metal component, the catalyst being a mixture of said mordenite and an aluminum halide sol; Produced by gelling the mixture and then calcining the gelled mixture, the alumina support material contains from about 20 to about 30 wt% molybnite.

As already mentioned, the process of the present invention is particularly directed to the treatment of hydrocarbons and hydrocarbon mixtures with boiling points above 6001''.

Since LPG production should be maximized, suitable feedstocks include heavy hydrocarbon fractions with initial boiling points of about 6001 to about 1000'F and final boiling points of about 650T to about 10501.

These feedstocks can be isolated from tar sands, shale and coal by known processing techniques.

Effluents from cokers, thermal crackers, fluidized catalytic crackers, crude oil processing units, and visbreakers can also be feedstocks for this invention.

The above feedstocks can be successfully processed in the present invention even if they contain sulfur.

However, it is preferred that the hydrocarbons fed to the second stage be essentially free of sulfur and nitrogen.

As mentioned above, the catalyst used in the first stage consists of a porous support material, a Group VI-B metal component, and a Group I metal component.

The catalyst may also contain a halogen component, preferably chlorine or fluorine, and may also contain a sulfur component.

This catalyst is commercially available, and many methods for producing it are known.

As mentioned above, the second stage catalyst is made by bonding a Group I metal component to a carrier containing alumina and mordenite particles.

Turning first to the alumina, the alumina is preferably porous and has a large surface area of from about 25 to about 500 m or more per adsorbent duram.

Suitable alumina materials are the crystalline aluminas known as gamma, eta and lanita aluminas, although gamma alumina gives the best results.

An essential requirement of the invention is that the alumina support contains finely divided mordenite particles.

As is well known to those skilled in the art, mordenite is composed of a three-dimensional network of interconnected tetrahedra of silica and alumina.

Tetrahedra is formed by four oxygen atoms around a silicon or aluminum atom, and the basic bonds between tetrahedra are through oxygen atoms.

The tetrahedra then form uniform cavities or channels interconnected with uniform pore openings in an ordered structure.

The ion exchange property of mordenite is due to the fact that aluminum is trivalent, and since aluminum is trivalent, alumina tetrahedra is negatively charged, and in order to maintain the electrical balance of the structure, Alumina tetrahedra can partner with cations.

The molecular sieve-like properties of mordenite are due to its uniform pore size, which is related to the size of the molecules, so that the molecular sieve-like properties of mordenite are related to the size of the molecules. Mordenite can be used to remove the mixture.

For purposes of the present invention, it is desirable to use mordenite with a pore cross-sectional diameter of about 5 angstroms, more preferably from about 5 to about 15 angstroms.

Usually mordenite. It is synthesized in an alkali metal form with one alkali metal cation bonded to each aluminum-centered tetrahedra.

This alkali metal cation can then be ion-exchanged with polyvalent cations such as calcium, magnesium, beryllium, rare earth cations, and the like.

Another method for treating alkali metal mordenite is to convert it into a hydrogen type by ion exchange with ammonium ions, followed by heat treatment preferably at a temperature of 300°C or lower.

Mordenite with a high silica to alumina molar ratio (for example -5 molar ratio) can be directly converted into the acid form in a suitable acid medium.

Although polyvalent metal type mordenite can also be used in the present invention, it is preferable to use hydrogen type mordenite, such as an alkali metal type, which is converted to the hydrogen type during the mixing procedure described below.

Preferred mordenites for use in the present invention are synthesized hydrogen-type and/or polyvalent metal-type mordenites.

In fact, the inventors have found that it is best to use synthetic mordenite with an effective pore diameter of about 4 to about 7 angstroms and a silica to alumina molar ratio of about 10 to about 25, preferably about 11 to about 16. We found that results can be obtained.

As is well known to those skilled in the art, mordenite has a crystal structure consisting of chains of five-membered tetrahedral rings, which are parallel chains of about 4 to 7 angstroms in diameter interconnected by small channels about 2.8 angstroms in diameter. It differs from other known crystalline aluminosilicates in that it is thought to be arranged to form channels.

Mordenite is characterized by the following formula.

0.9±2M 20: A1203: X5102
(Anhydrous type) Here, M is a cation that balances the electron valence of tetrahedra, n is the valence of M, and X is a constant, generally having a value of 9 to 11, usually about 10.

Synthetic mordenite is available from a number of manufacturers, one of which is Two-Tone Company of Wester, Massachusetts, USA.

Regardless of the method used to mix the mordenite particles into the alumina carrier, it is an essential requirement of the present invention that the mordenite particles be directly added to the alumina hydroxy halide sol before the sol gels.

Although fluorine, bromine or iodine containing sols may be satisfactory in some cases, the inventors have found that substantially pure aluminum metal is dissolved in hydrochloric acid to give an aluminum to chloride weight ratio of from about 1:1 to about 1. It has been found that the best results are obtained using aluminum hydroxychloride at a ratio of .4:1.

Further, it is preferred that the sol has a pH of about 2 to about 5.

One of the advantages obtained under these conditions of the present invention is that it is relatively easy to uniformly disperse mordenite particles in the sol.

However, the most important advantage is that the sol reacts with mordenite and imparts some fundamental changes to the mordenite structure, making it significantly superior to reactions involving carbonium ion intermediates such as hydrocranking. It is believed that a support that exhibits a catalytic effect can be obtained.

Therefore, it is an important requirement in the present invention that the second stage catalyst be prepared by the following process.

That is, the method involves mixing finely divided mordenite particles with a sol of aluminum hydroxyl halide, gelling the resulting mixture into a hydrogel or hydrogel particles, and then subjecting it to standard aging, washing, drying and power-calcining treatments. This is a method of finishing the catalyst into a catalyst.

In the present invention, the catalyst may be in any desired shape, such as spherical, pellet, pill, cake, extruded, powder, or granular shapes.

However, a particularly preferred catalyst shape is spherical, the spherical catalyst being prepared by reacting an alumina hydrosil, preferably aluminum metal, with hydrochloric acid, and treating the hydrosil with a suitable gelling agent such as hexamethylenetetramine. The finely divided mordenite particles are uniformly distributed in this droplet, and the resulting mixture is then dropped into oil, or after mixing mordenite with hydrosil, a gelling agent is added. It can be produced continuously by the known oil drop method, in which a dripping liquid is prepared by adding the liquid, and the dripping liquid is dropped into oil.

In each case, the droplets of the mixture are held in the oil until they transform into substantially spherical hydrogel particles.

The spherical particles are then successively subjected to a special aging treatment in oil and in an ammoniacal solution to further improve their physical properties.

Alternatively, the hydrogel spheres can be pressure aged in dripping oil or a similar oil, in which case atmospheric pressure aging in an ammoniacal solution is not necessary.

Suitable conditions for pressure ripening include a temperature of about 0°C to about 300°C and a pressure that can maintain the system in a liquid phase.

The resulting aged gelled particles were then washed and heated to about 300T.
After being dried at relatively low temperatures of ~400'F, approximately 85
It is subjected to a power firing treatment at a temperature of from below 0 to about 1300'F for about 1 to about 20 hours.

This treatment converts the alumina hydrogel to the corresponding crystalline gamma-alumina.

The details of the oil drop method are detailed in US Pat. No. 2,620,314.

The amount of mordenite in the alumina carrier is about 20 to about 30w
Preferably, it is t%.

As used herein, "finely divided" means using mordenite with a particle size of from about 1 to about 100 microns in average diameter; when using particles with an average diameter of less than 40 microns, for best results.

The second stage catalyst may include a halogen component.

Although the details of the bonding form between the halogen component and the alumina support are not fully known, it is generally considered in the industry that the halogen component is bonded to the alumina support or to other components of the catalyst. .

The bonded halogen may be fluorine, chlorine, iodine, bromine or a mixture thereof; among these, fluorine is
More preferably chlorine is desirable for the present invention.

As already mentioned, the halogen component is introduced into the catalyst during its preparation.

However, if desired, additional halogen can be added to the force-calcined catalyst as an aqueous solution of an acid such as hydrogen fluoride, hydrogen chloride, hydrogen bromide, and the like.

Furthermore, additional amounts of halogen components can also be incorporated into the catalyst when it is impregnated with the Group I metal component.

In any case, the final catalyst contains about 0.0 halogen on an elemental basis.
1 to about 1.5 wt%, preferably about 0.1 to about 1.0 w
The halogen component can be bound to the carrier so as to contain t%.

The essential component of the second stage catalyst is a Group (I) metal component.

The Group I metals can be present in the final catalyst composition as compounds such as oxides, sulfides, halides, or in elemental form.

Generally, the amount of Group I metal component present in the final catalyst is small compared to the amount of other components associated with the catalyst, and the amount ranges from about 0.05 to about 0.05% of the final catalyst composition on an elemental basis. Approximately 1.
It is 5wt%.

Suitable Group I metals include platinum, iridium, osmium, palladium, rhodium, ruthenium, nickel, cobalt and arsenic, with palladium and platinum being preferred.

The Group I metal component can be introduced into the second stage catalyst composition by any suitable method such as an ion exchange method using a suitable solution of the metal component and/or an impregnation method.

However, in the present invention, it is essential to introduce the Group 1 metal component into the catalyst carrier prepared by the method described above after the power calcining step.

Therefore, one of the preferred methods for preparing the bifunctional catalyst of the present invention is a method of impregnating a power-calcined catalyst using a water-soluble compound of a group (I) metal component.

For example, the platinum component can be added by mixing the carrier with an aqueous solution of chloroplatinic acid.

Regardless of how the Group I metal component is bonded to the catalyst, the resulting bifunctional catalyst generally has a molecular weight of about 200T to about 600'
It undergoes a drying process for about 2 to 24 hours at a temperature of F, and is finally dried at a temperature of about 700,000 to about 1,100 below, about 0.5 to about 1
0 hours, preferably 1 to about 5 hours.

The force-calcined bifunctional catalyst composition is preferably subjected to a reduction treatment before being used in a hydrocarbon conversion reaction.

This reduction step is carried out to uniformly and finely disperse the Group I metal component in the carrier material.

In this case, preferably substantially pure dry hydrogen is used as reducing agent.

The reducing agent is contacted with the power calcining catalyst at a temperature of about 800'F to below about 1200F for about 0.5 to 10 hours, thereby substantially reducing the Group I metal component to its elemental state.

This reduction process can be carried out in the reactor as part of the start-up procedure if desired.

Although not necessarily required, the reduced bifunctional catalyst may be subjected to a pre-sulfurization treatment to give the catalyst composition a content of about 0.05 to 0.05 on an elemental basis.
Preferably, about 1.5 wt% sulfur is added.

This pre-sulfurization process involves hydrogen sulfide, low molecular weight mercaptans,
This is carried out in the presence of a suitable sulfur-containing compound, such as an organic sulfide, and hydrogen, typically by adding the reduced catalyst to a mixture of hydrogen and hydrogen sulfide in an amount of about 10 moles of hydrogen per mole of hydrogen sulfide. The sulfur gas is brought into contact with the sulfur gas under conditions that allow the desired addition of the sulfur component, for example, at a temperature in the range of about 50°C to about 1100°C.

The reduction and presulfidation of the second stage catalyst can alternatively be carried out simultaneously, but in this case the power calcining catalyst is a combination of hydrogen sulfide and hydrogen containing about 10 moles of hydrogen per mole of hydrogen sulfide. gases, such as a mixture of
The contact is made under conditions of about 1100'F.

According to the invention, under the conditions of hydrocarbon conversion, the first and second
In the conversion zone, the hydrocarbons come into contact with a catalyst of the type described above.

This contacting can be carried out using catalysts in fixed bed systems, moving bed systems, or fluidized bed systems; however, in view of expensive catalyst attrition and operational advantages, fixed bed systems are preferred.

If a fixed bed system is utilized, the feedstock is preheated to the desired reaction temperature by suitable heating means and then passed to the conversion zone containing the catalyst as a fixed bed.

Of course, the first or second conversion zone may consist of a single reactor, or it may consist of a plurality of reactors with appropriate equipment placed between the reactors to maintain the inlet temperature of each reactor at the desired conversion temperature. It can be configured with a reactor.

The reactants can also contact the catalyst bed in an upflow, a downflow, or a radial flow.

Furthermore, when the reactant comes into contact with the catalyst, it may be in a liquid phase, a gas-liquid mixed phase, or a gas phase.

The heavy hydrocarbon fraction is fed to a first stage reaction zone maintained under hydrocracking conditions.

An effluent containing hydrocarbons in a lower boiling range than the feedstock is removed from the first stage reaction zone, and LPG is extracted from the effluent.
and other normally gaseous compounds such as ammonia and hydrogen sulfide are stripped.

At least a portion of the stripped product is introduced into a second stage conversion zone maintained under hydrocracking conditions.

An effluent is removed from this second stage conversion zone which is sent via a condenser to a separation zone typically maintained between about 50 below and about 125 below, where the hydrogen-rich gas is separated from the LPG
separated from the liquid product rich in

Preferably at least a portion of this hydrogen-rich gas is removed from the separation zone and then passed through a suitable compression device to a second
Returned to stage conversion zone.

After the liquid phase from the separation zone is removed from the zone, L
It is usually processed in a fractional distillation system to recover PG (liquefied petroleum gas) and other light fractions.

The following examples specifically explain the method of the present invention and demonstrate the effects achieved by the present invention.

It should be noted that this example merely shows one method of implementing the present invention, and does not limit the present invention in any way.

The boiling point range of the example is 596 below to 654T, and the sulfur content is 1.
Diesel oil with 0wt% was selected as the raw material for LPG production.

This diesel oil was heated to a pressure of 1500 psig in a hydrocracking reaction zone containing a catalyst consisting of nickel and molybdenum supported on a silica-alumina support.
, a liquid hourly space velocity (LH8V) of 0.8 hr', and a hydrogen circulation ratio of 12000 standard cubic feet per barrel (SCFB) to obtain kerosene with a final boiling point below 550 and a sulfur content of only 3 ppm.

The kerosene is stripped to remove light fractions and hydrogen sulfide, and then transferred to a second hydrocracking reaction zone containing a catalyst consisting of platinum, alumina, and mordenite prepared as described above. At a pressure of 1000 psig and a liquid hourly space velocity of 3. ]1r-1, treated under the conditions of hydrogen circulation ratio 100005CFB and 75wt
% LPG and 25 wt % pentanes were obtained.

As is clear from the above description, according to the present invention, LPG can be produced to the maximum extent from a high boiling point hydrocarbon feedstock.

Embodiments of the invention will now be listed.

(1) The method according to the claims, wherein the heavy fraction is diesel oil or gas oil.

(2) The method of claim 1, wherein the catalyst composition in the first reaction zone comprises an aluminosilicate support material, a nickel component, and a mordenite component.

(3) Hydrocracking conditions are pressure about 300 to about 2
000 psig, temperature about 600T to about 8501, LH
8V about 8V5 to about 10hr-1, hydrogen circulation ratio about 5000
150,008 CFB.

(4) A method according to claims, wherein the catalyst composition in the second reaction zone contains platinum or a platinum compound.

(5) The method of claim 1, wherein the catalyst composition in the second reaction zone contains palladium or a palladium compound. (6) The catalyst composition in the second reaction zone contains palladium or a palladium compound.
A method according to claims containing 5 wt% halogen.

(The catalyst composition in the second reaction zone is about 0.1 to about 1.5
A method according to claims containing wj% sulfur.

Claims (1)

[Claims] 1(a) a porous carrier material, a Group VI-B metal component, and a
In a first reaction zone containing a catalyst composition comprising a group metal component, a heavy hydrocarbon fraction with a boiling point of about 600'F'' or higher is converted to a lower boiling point hydrocarbon. (b) prepared by mixing finely divided mordenite particles into a sol of aluminum halide and post-gelling and post-calcining this mixture to obtain a homogeneously distributed In a second reaction zone containing a catalyst composition having a Group I metal component bonded to an alumina support material containing about 20 to about 30 wt% mordite, the low boiling point hydrocarbons described above are
reacting under hydrocracking conditions selected to produce PG; (e) LP from said first and second reaction zone effluents;
A method for producing LPG from heavy hydrocarbons, comprising: recovering G.